The invention relates to the technical field of motion function analysis, and in particular to a balance index model in motion function analysis based on big data. The balance index model is constructed through the steps of testing an overall stability index of each player in the whole team by use of a Biodex isokinetic muscle strength assessment training system, and calculating a standard value M and a standard deviation SD of the overall stability index of the whole team; and calculating a balance energy bar numerical value according to a formula. Through establishment of the balance index model in the motion function analysis based on the big data, a balance index is directly converted into a form of an energy bar score which has practical reference significance to a match, a coach is enabled to guide the match better according to the state of each player, thus, the value of the player is embodied; and the balance index is directly converted into the form of the energy bar score, the player can better locate the position of own balance capacity in the whole team, thereby exciting the competitive spirit of the player, promoting the player to train actively according to weakness indexes and being beneficial to improving the overall strength of the whole team.